Because he is all we can think about right now.
I didn't know him, obviously. But here's what I received from Robin Williams and how I most remember him.
There is a scene in Good Will Hunting (the performance for which Williams won the Oscar for Best Supporting Actor):
In this scene, Matt Damon's character reveals to Williams (his therapist) that he was beaten as a child. Williams says "It was not your fault." Damon nods "Yes, yes, I know." Williams repeats, "It was not your fault." Damon, impatiently, "I know."
He repeats it again and again until Damon's character breaks down and admits he believed the beatings were his fault.
It is one of the most powerful moments on screen. A simple exchange of dialogue delivered by two truly fine actors. That scene has been called into my consciousness in some pretty tough times and saved me. It wasn't the words or the production values or the media buzz or even the Oscar win that gave that moment its power--it was Robin Williams.
I wish he was still here.